Population III (Pop. III) stars, as of yet, have not been detected, however as we move into the era of extremely large telescopes this is likely to change. One likely tracer for Pop. III stars is the He iiλ1640 emission line, which will be detectable by the HARMONI spectrograph on the European Extremely Large Telescope (ELT) over a broad range of redshifts (2 ≤ z ≤ 14). By post-processing galaxies from the cosmological, AMR-hydrodynamical simulation newhorizon with theoretical spectral energy distributions (SED) for Pop. III stars and radiative transfer (i.e. the Yggdrasil Models and cloudy look-up tables, respectively) we are able to compute the flux of He iiλ1640 for individual galaxies. From mock 10 h observations of these galaxies we show that HARMONI will be able to detect Pop. III stars in galaxies up to z ∼ 10 provided Pop. III stars have a top heavy initial mass function (IMF). Furthermore, we find that should Pop. III stars instead have an IMF similar to those of the Pop. I stars, the He iiλ1640 line would only be observable for galaxies with Pop. III stellar masses in excess of $10^{7}\, {\rm M}_\odot$, average stellar age $\lt 1\, {\rm Myr}$ at z = 4. Finally, we are able to determine the minimal intrinsic flux required for HARMONI to detect Pop. III stars in a galaxy up to z = 10.

中文翻译：

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通过氦 1640 Å 发射线用 ELT-HARMONI 预测 III 族恒星的可观测性

迄今为止，尚未发现第三族（Pop. III）恒星，但是随着我们进入超大型望远镜时代，这种情况可能会发生变化。流行音乐的一种可能的示踪剂。III 星是 He iiλ1640 发射线，可以通过欧洲超大望远镜 (ELT) 上的 HARMONI 光谱仪在广泛的红移范围内 (2 ≤ z ≤ 14) 检测到。通过对来自宇宙学、AMR 流体动力学模拟新视域的星系进行后处理，以及 Pop 的理论光谱能量分布 (SED)。III 星和辐射传输（即分别为 Yggdrasil 模型和多云查找表）我们能够计算单个星系的 He iiλ1640 通量。通过对这些星系的模拟 10 小时观测，我们表明 HARMONI 将能够检测到 Pop。星系中高达 z ∼ 10 的 III 星提供了 Pop。III 星具有头重初始质量函数（IMF）。此外，我们发现应该流行。III 星的 IMF 与 Pop 相似。I 星，He iiλ1640 线只能在有 Pop 的星系中观察到。III 恒星质量超过 $10^{7}\, {\rm M}_\odot$, 平均恒星年龄 $\lt 1\, {\rm Myr}$ 在 z = 4。最后，我们能够确定HARMONI 检测 Pop 所需的最小内在通量。星系中的 III 星，z = 10。我们能够确定 HARMONI 检测 Pop 所需的最小内在通量。星系中的 III 星，z = 10。我们能够确定 HARMONI 检测 Pop 所需的最小内在通量。星系中的 III 星，z = 10。